Air bleeding apparatus for an autoclave

Abstract

A device for removing air from the steam chamber of an autoclave includes a sealable sterilization chamber for receiving items to be sterilized. The chamber is sealed and the pressure and temperature therein monitored by sensors. Vapor for sterilizing items is generated in the chamber by a heater. Air is removed from the chamber through a relatively large vent and a selectively activated valve for opening and closing the vent. A digital controller receives the monitored temperature and pressure of the chamber as inputs, compares these empirical values with standard values and, on the basis of the comparison, generates a control signal to selectively open or close the valve. The vapor used in steam and the standard values are a set of coordinates, which when plotted on a pressure/temperature graph, would yield a curve characteristic of saturated steam. The standard values are stored in a memory accessible to the microprocessor. Below a given chamber temperature, venting is discontinued whenever a saturated steam condition is sensed, and above a given chamber temperature, when saturated steam is consistently achieved, the pre-conditioning stage is ended. The entire process of pre-conditioning is controlled by the digital controller, preferably a programmed microprocessor. The time period between successive monitorings of the chamber temperature and pressure is shortened as the temperature in the steam chamber increases.